1. Field of the Invention
The present invention relates generally to a hinge device applicable to soft display module, and more particularly to a hinge device assembled with an electronic apparatus. The hinge device includes a joint unit assembly having rotary shafts and motional shafts in adaptation to the operation of the electronic apparatus for moving the joint unit assembly.
2. Description of the Related Art
There are various electronic apparatuses provided with covers or display screens, such as mobile phones, notebooks, PDA, digital image capturing devices and electronic books. The covers, display screens or viewers are pivotally mounted on the electronic apparatuses via pivot pins or rotary shafts, whereby the covers or display screens can be freely rotated and opened/closed under external force.
In order to operate the display module (such as the screen) and/or the apparatus body module of the electronic apparatus in more operation modes and application ranges, a conventional dual-shaft mechanism mounted between the display module and the apparatus body module has been developed to rotate the display module and/or the apparatus body module by different angles in accordance with different operation modes. For example, U.S. Pat. No. 7,512,426 B2 discloses a mobile communications device with synchronizing hinge.
With respect to the operation, motion and structural design of these pivot pins or hinge devices, the conventional pivot pin device cannot be mounted on a flexible soft display screen or display module in adaptation to the flexion and rotation of the soft screen. This is because:    1. In the case that the conventional pivot pin device or rotary shaft is applied to a flexible soft display screen, the rotary shaft will be relatively positioned on outer face (or outer end face) of the display screen, while the display screen is relatively positioned on the inner (end) face of the rotary shaft. There is a certain distance between the display screen and the axis of the rotary shaft. Therefore, when the display screen is flexed with the axis of the rotary shaft positioned on relative outer end serving as the rotational fulcrum, the display screen on the inner face of the rotary shaft will be squeezed and crimped. This is not what we expect.    2. When the existent rotary shaft or pivot pin device is applied to a flexible soft display screen, the soft display screen cannot be immediately truly located after flexed or opened/closed.
The conventional rotary shaft and the relevant connection components thereof have some shortcomings in use and structural design that need to be overcome. It is therefore tried by the applicant to provide a hinge device applicable to soft display module to change the use form, widen the application range and facilitate the operation of the conventional rotary shaft and thus eliminate the shortcomings existing in the conventional rotary shaft. Especially, the hinge device is applicable to an electronic apparatus with soft display screen or display module in condition of simple structural design and simple operation of the hinge device, rotary shaft or the relevant connection components to solve the problems of the conventional rotary shaft (that when the display screen is flexed or rotated around the rotary shaft, the display screen will be squeezed and crimped and the soft display screen cannot be truly located). Also, a frictional torque system and/or torque mechanism is further provided to enhance the locating or fixing effect of the hinge device in operation. Moreover, according to the specification, the number or torque of the hinge device and/or torque mechanism can be easily changed or adjusted to meet the pattern design requirement of lightweight and slim configuration of electronic apparatus.